Processes for the production of expanded polystyrene foam blocks are known in the art. Thermoplastic beads, e.g., polystyrene beads, containing a blowing agent, normally hydrocarbon mixtures having a boiling point between 80 to 110 degrees Fahrenheit, are pre-expanded in a vessel by, e.g., introducing steam into the vessel or by controlled heating. After pre-expansion, the beads may be placed in a storage container before molding. One known method and apparatus for expanding loose fill material, such as polystyrene pellets, is disclosed in U.S. Pat. No. 4,790,967.
In the expanded polystyrene foam industry, the cutting process is normally performed most economically using known hot wire cutters. In such hot wire cutters, two parallel electrically isolated metal bars are spaced at a certain distance apart and energized electrically with a low voltage, e.g., 40 volts. Many high resistance wires, e.g. chrome nickel wires having an approximate 0.012 diam., are tensely held in parallel between the isolated metal bars. The current that flows through the high resistance wires heats them up so that they can therefore "melt" the polystyrene when it is passed through the wire "harp".
As discussed above, the production of loose fill materials are known in the art. The most commonly used materials are expanded polystyrene foam (EPS, recycled or "virgin"), starch-based loose fill, corrugated side trim, molded paper pulp, wood shavings, popped corn, etc. A comparison of various loose fill cushioning materials based on protective and environmental performance is well described in the article entitled "Comparison of Various Loose Fill Cushioning Materials Based on Protective and Environmental Performance", Packaging Technology and Science, Vol. 7., 229-241 (1994).
Advantageously due to a relatively low price, an extremely low weight in comparison to other products, as well as the possibility of being recycled while not containing any chlorofluorocarbons (CFC), the expanded polystyrene foam (EPS) type of loose fill packing material has been used in large quantities in the industry and has currently the highest percentage of market share. Probably the most used shape of EPS is a "peanut" shape in the form of an "m". The "peanut" shape is formed of an extruded pellet of expandable polystyrene which is later expanded using steam or any other heat source. Another type of "peanut" shape has the form of an "8" and is made of recycled EPS which is then extruded afterward.
All of the known loose fill materials suffer a common problem, especially the loose fill manufactured with EPS, in that they have a large volume and therefore occupy a large amount of space. Of course, this is disadvantageous and inconvenient when it comes to storing the material in warehouses and transporting the material. Thus, the known materials have high transportation and storage costs. Normally, the expanded "peanuts" are transported in fourteen cubic ft polyethylene bags, which are expensive to store and transport.
There is therefore needed a process and product for cutting and packaging the EPS loose fill material so that it can be transported in a "reduced volume" manner so as to diminish the above-mentioned costs while not sacrificing the effectiveness of the product.
There is also needed a process and product for cutting and packaging EPS loose fill material having varying densities in order to protect objects of varying weight.